Home
Class 12
PHYSICS
A thin film of thickness t and index of ...

A thin film of thickness `t` and index of refractive `1.33` coats a glass with index of refraction `1.50`.What is the least thickness `t` that will strong refelct light with wavelength `600nm`incident normally?

A

`225nm`

B

`300nm`

C

`400nm`

D

`450nm`

Text Solution

Verified by Experts

The correct Answer is:
A
for constructive interference
`2mut=nlambda`
`t=(nlambda)/(2mu)`
`t_(min)=(lambda)/(2mu)rArr t_(min)=(600nm)/(2xx1.33)`
`t_(min)=225nm`
Promotional Banner

Similar Questions

Explore conceptually related problems

A thin uniform film of refractive index 1.75 is placed on a sheet of glass of refractive index 1.5. At room temperature (20^(@) C) this film is just thick enoungh for light with wavelength 600 nm reflected off the top of the film to be canceled by light reflected from the top the glass. After the glass is placed in on oven and slowly heated to 170^(@) C , the film conceals reflected light with wavelength 606 nm. The coefficient of linear expansion of the film is (ignore any changes in the refractive index of the film due to the temperature change)

A ray of light 10^(-9) second to cross a glass slab of refractive index 1.5. The thickness of the slab will be

A plastic film with index of refraction 1.80 is put on the surface of a car window to increase the reflectivity and thereby to keep the interior of the car cooler. The widow glass gas index of refraction 1.60. What minimum thickness is required, if light of wavelength 600 nm in air reflected from the two sides of the film is to interfere constructively? (b) It is found to be difficult to manufacture and install coatings as thin as calculated in part (a). What is the next greatest thickness for which there will also be constructive interference?

High-quality camera lenses are often coated to prevent reflection. A lens has an optical index of refraction of 1.72 and a coating with an optical index os refraction 1.31. For near normal incidence, the minimum thickness of the coating to prevent reflection for wavelength of 5.3 xx 10^(-7) m is

If refractive index of glass is 1.50 and of water is 1.33, then criticle angle is

White light is incident normally on a thin glass plate of refractive index 1.5. Calculate the minimum thickness of the film for which the wavelength 4200 Å is absent for the reflected light.

If the refractive index from air to glass is 1.5 ,and the refractive index of water is 1.33. What is the refractive index from glass into water?

Our disscusssion of the techniques for determining cosntructive and destructive by reflection from a thin film in air has been confused to rays striking the film a nearly the normal incidence.Assume that a ray is incident at an angle of 45^(@) (relative to the normal ) on a film with an index of refraction of sqrt(2) .Calculate the minimum thickness fro constructive interference for issodium light of wavelength 600nm .